Thermoplastic Vulcanizates of PBS- EVA and Cellulose Nanocrystal: a Comprehensive Experimental Study on the Mechanical, Rheological and Shape Memory Behavior

Abstract

Poly (butylene succinate) (PBS) is among the least studied biodegradable polyesters, where its high crystallinity and low extensibility had limited its wide- spread application for packaging. In this work, we designed a series of thermoplastic elastomers (TPEs) and vulcanizates (TPVs) based on PBS and ethylene vinyl acetate (EVA) with a focus on its modulus (\(\:E\)) and elongation at break (\(\:{\epsilon\:}_{b}\)). The TPEs showed poor mechanical performance and using dicumyl peroxide (DCP), applied directly (D) and as a masterbatch with EVA (M), resulted in superior mechanical performance with the TPV based on the PBS: EVA composition of 90: 10-D showing the highest \(\:{\epsilon\:}_{b}\) of 637.6% compared to the \(\:{\epsilon\:}_{b}\) of 108.1% for PBS. The \(\:E\) value of the TPV was 139.1 MPa compared to 353.2 MPa for PBS, which was due to the presence of EVA rubber. However, presence of 2% cellulose nanocrystal (CNC) increased \(\:E\) to 225.9 MPa with the \(\:{\epsilon\:}_{b}\) of 463%. Both PBS and the optimal TPVs showed high shape fixity even at 25°C due to its high crystallinity, while the TPVs and especially, the TPV- CNC (2.0%) showed higher recovery ratios caused by formation of an elastic 3D network of both the cured EVA droplets and CNCs.